Dry kiln



eilen Myl` invention "relntes -to t kilns pand e perticularly` kilns i of-` the linternal fan within the kilnpis eiectedd ,sibstentiellyV troyensmeenslofthe rotetfmerfwweri'driven reim' fans peretivelxjfl mounted' withiniythe kiinfiin e peirs, ither above, below; or lntfone `sigle `oi.' thel ineterial fintitbeyiilljiel.:` i; lAnvobjectofin l e e ir `circulatingsystem` `withinja. kiln. t `Another object 4of my inventionxis units; eaonjopen on` one` of its"` sidesyend lieving "its two ends, which fans `maye'fiect intke ofkiln tniosphereyetthetwoiends ofthe and dis- `inone stream `whenil-thefans are roteting in one ncliriaetion,` "and` eieet; intake "ofkiln atmosphere et` one; `sideof n theunit and discharge; oi kiln `itt-- ospnerefrom thetivd ends of `theunitlin two ste directiom t 't Another objectlof my invention is to provide novel;` `means of taking n in `fresh` airvfromi" two `fresh air conduits intothe5ki1n-tofthefsuction side i of the fansystem from two lsides of thegkiln e eitherfdireotion offen rotation,`

` LAIlOther `Object ofymy invention iS kiln control, in s. kiln inwhichstocks ofydifferent itinitieli moisture content dried attinthe different form moisture` `content t in the i seine length of 'meifii f ,i L

Another object `of lmy` invention is tdfeffect a uniform application of heat isubstntially: the full olii,` xilnicomnlenkof Oregon, corpo-i n con ypefink` whien n the circuletionofflthe `iitniosplziere ersely` across wistnock i loads i g stacked therein,` by

nrovidefa novel n n oefende withinbekilngspaced compartment eirgirculating i pgn-eq jens'vopemtiirelyernounted,` one ,in each of "n t tneappendedclaims berge yof -kilnetmosphere Vfromtonei oflts sides i l reeins whenthe tens are rottlnsvin thefoppo- Another t objecti"`of t invention is` J fa." novelfresh--nair end `Ventilating systernforv: a oflilgure` I.`

Anotheryebjeet erfnig'f `invntiofiris2te provide utomatic control of freshiitir` intakefinto the kiln t i regardlessof ,the directionof aircirculation'with-t` t t t @een a novel `inethoii-ofiind inter-related sppariatusfor` ends of,` the` kiln respectively control their drying leveremployeii' in Eigures Vriend ostfiuef 'll t t t teininjmhiener nieieture "een'tent `wenn previueiimfomi drm n y. e Anotherlobject'ofni `1 invention for effecting e greater `volume"ofWitircirculetion at the endsadlacent to thefnvdoors" of"` the` kiln e l `Witheetprivitrine imjiizitiieinerLveirjeiiietieii.` g

*y VAnotherWobjeotl my invention is to eect extra `heetingof"tlieiilre'txthe'entisi` i doors "of the kiln jtooompensete for losses there, "without producingf longitudinal circula.-

`after specified in detail land suecinctl`ytilei3x1`el` in In the ccompanying drawings wherein 'rny invention is;` illustrted in the present `preferredfforni of embodiment, l f t `Figure I` isgaljtrnsverse `vertital section of ka. `n singletreek kiln embodying my reinvention; n t Figure mis transverse vertical section et a e deebie treeikim snowing a modined 'eireinetingt usystem to thtshoym in .t

e Figure III tsa longitudinelfvertical" takenalong the line of lellgreI. n ngurerv iii` e pien view `teuren eiog the line Figure-V of afmodmeq fermor.i'riashair` duct system of t met shown inriguresr end n Figure@ ie e perrier 1 f tudirieigveriieei section `tellennleng the line of Figui-edv gute ise, nien `vievf'teken elong the Q Figure Xi is `i, `.detailed cross' sectionof e motor e vrtferperwn;

e *Figure XI `erosie seitiftlonv of `motor lever with t mechanism; for operating ventilator dempers.

i Figure xn ie e ,verticali seetien through the pin` i boi enautometio rightengle damper for a` fresh `airvport nd duct, illustrated in Figure IX. e

Figure is crossfseetion of e. preferred form of diaphraslnvelve whichcontrolsthe steemsupf ply to `thelie'tingfand? sprey pipes withinlthe kiln.` i engthfof a kiln containingistock varying in inii Referring to theinumeials on the drawingsl indicates Ltlienoor,

` e e vwithin e. kiln a. transversecirculetionwith mens" adieeent te the t weet eeneeiijuiee ieyylieveeiienwm be herein! D section" 1s iffortifiedineeinemeen; tially diagrammatic takenalong the line V`V of` Fiiruren` v e e "t2 and l :the side Walls; and "4theroixitofthekilmv u t n system comprises ssn u unser-toog erabiybeamslwhioharesupportedbytheside wallsl'andiofthekilnandwhichalsomaybe I mppteobytnefmctsidenmsansnm lllnFlgureII.

l and 1 are preferably stacked stickers 'il between layers oi material to be dried, provi interstices I1 open for transverse circulation across the stock loads between Il. The stock,whe`n lumber, for exis preferably stacked edge to edge between on the stock loads either fiat or edgewise.- I illtrates the embodiment of myinemploylna edge piling of lumber. The ,preferably havestake pockets il, at their ends.'having a recess for the in- I-beam or other stam 2|which supaide tiers Ill oilumber. I `preferably binder Il e ,l Vtransversely across f the holding` the top ends of the Il in position 'niebinders il may be of f -known *mi such -as, rigid binders, Y, fete., well known in the art. Iwo il, 'one bunk li, two stakes III, and one 2 in a seriesto receive an edge stock load of lumber, andythese units may bespacsdasde'sirodfeaoh load having at a isa'sttwo units and preferably more. y Y

ligure niliustratea'the embodiment of my inp Y ilat stacking in 'a double track The" Vioadal and 1 are disposed on tracks extending through the kiln mbatantially parallel to andion oppositefsides of een the

' maybe constructed with any preferable number oltraeksfor which my'invention may be oper- The drawings illustratekilns in which the air circulating is 'located below the'rtracks. however. that thev kilns lmay "be in effect inverted and the air-circulating system may be disposed above the stock loads. lIn this case the tracks would preferably be'supported Y 1b! the door, instead oi' on Ibeams l.

` y' ll A distinctive feature of` yinventionfis to be *found in the air circulating system of the apparatus. VThe air circulating system comprises Y y compartment air circulating units 30, each -of which is openl yon oneof its sides. The top 7 side is open'in kilns having the air circulating system below thestock loads.L Between each two' adjacent Aspaced ycuunpartments 3l isa covered passageway", vopen onftwo sides and having a passageway cover I! .'-This covernconnects the i sanpartment substantially at ed asa unit. Several units suponen: mustang mnwmen compartment walls are curved, or having a shape other than rectangular in horizontal cross section, the purposes and enects of the parts corresponding to the parts namedwould be the same.

Connecting with the top edges of the compartment side walls y,and Il, and of the passageway cover l2, are the baille plates 42, which may be ilpstanding or inclined and may extend substantially the. full length of the kiln as illustrated in Figure I. Thesebaiile plates l! are not indispensableas in cases where the side wall 33 extend up to rail level to make substantial closure between the side walls Il and the corner of the stock loads, as in Figure II, providing open means of communication between the compartment units 30 andthe corridor 4B which has a plurality of outlets through stock loads forming the sides of the corridor as in Figure II. The baiiles 42 in Figure I, or Il in Figure II may be used if deaired to eiiect more complete closure between the side walls, and the corners of the stock loads.

the compartments and from the side edges of the passageway cover I! upwardly, for example in Figure I, to form substantial closure with the side cornersl of the stock loads 0.

In ilat'piling embodiments of my invention, as

illustrated in Figure l1, the air circulating system-is disposed between and below` the stock loads.y It isunderstood, however, that this circulating system mayl be disposed in a similar po- Asition in single track kilns in which each stock load is partially dividedfbyra central flue, similar to the corridor Il between the stock loads l and 1 in Figure II, forl example. It is immaterial whether or not two vstock loads l and 1 are stacked with the'corridor II between them, or whether one stock load is partially divided by central iiue corresponding to ll, and preferably covered vat the top with a'cover plate corresponding to the ceiling balies 4I.

. vIn the edge piling embodiments of my invention, as shown in'Figure I, I preferably provide corridors "and 4I on opposite sides respectively oi the'stock loads l, between the stock load and the side wallsof the kiln.

In theiiat piling embodiment of my kiln If preferablyV provide corridors 4l mediaily and extendinglongitudinally within the-kiln, and cor- .V ridors I1 and 4l at the sides `between the stock loads and the side walls oi the kiln. In Figures Iand II the corridors I1 and are'shown to extend from the ceiling to the iloor of the kiln sndto connect at their lower portions with the pasageways Il, for example in Figures I and II. In Figure II the corridor ll extends from the top of the stock load to the bottom of the compartments 3l of the air circulating system, but corridor Il in Figure II, may be considered to vcoresponcl plenum chamber in `Figurelrin` Theil fans 3l and `ll" are preferably right and ftjhand having blades'respectively set "at `d itfer- "entlanglestand opposed in thejdirectionof their dischargemontd in pairson afcommonshaft tandsflllsupported by the floor i `of the kiln whenftheair circulating system is below the stock bricantfthrough the oilcups "I4 for example: The

. lian 1 shaft lil is driven preferably `byany suitable *driving means; such asjfor example, anelectric wr: essential feature ofimy linvention consists in thei design 1 of` the air "circulating s ystem l and the air circulation 1 therefrom. I The discharge of ekiln atmosphere `from the compartments `Il dfll inthe" two directions respectively of frotaents` moving "substantially vertically from Aeach ornpartment 3h0 into theplenum` chamberf *or `teractirigjcurrents"from two adjacent compart-` ments sin the passageway 3| wherethey move he passageways fl I l in` thefreverse ldirectli'in of ri` rotation; :Infeachdirection of'fari rotation the kiln atmosphere passes across the stock )loads and fhacl` to the fans; 1in continuous recirculation.

i `Attention is calledto the method oflvadmittingj fresh; airfyinto the kiln; l i Thefreshair `conduits i501 andllvon "opposite sides of the kilnware pro- `vided withfresh airjducts 82 and Il respectively. The i fresiri airl` conduits are preferably provided `wlthjend` doorsfll and il; whichi may be `opened r11` closed t6 supply fresh *airi to the conduits 6I and and through the` air ducts I2 and "tinto thewlrilnv: chamber.` Iv also" preferably` provide louvers," lorf dampers.` 4i I which .may be disposed iinltheffresh air ducts l2 and. Ihese dampers rulouvers may beindividualiy or collectively ad- `amount lofi open areawin the fresh air ductsl! and Il between` the conduits lland i I andthe `kiln charnbenw.sul` l i u` f It isgunderstood thatfthe air circulation `withw inthe ljkiln is 1 reversible and lit is intended; in one form of embodiment of my invention,` illustrated `in Figures IfitnrlfIV;` to luseone oi'jthe `fresh air thelfans,` :thus when the J fans are discharging-atmosphere fupwardlyfrom the compartments, as 1inllll'igui'e` Ivi. for example.` the `fresh `air con# duitvllyand the air` duct l! areemployed for-the intakeot fresh airinto the kiln chamber. `When the fans are rotating.. in thereverse direcltion Wto? `discharge kiln i atmosphere laterally `through thepasslaeways- Il. at the sides of the, `stock loads I,lfor`l'example, in Figures I and IV, ltheffreshfairy conduit Il` and the fresh air ducts "diritti thifpugn thefsiruucts u mtbth `einnimmt. ment" IM th fair `being discharged from the com-1 partment into thief passageway l I and Ithon flaterally and upwardly at the sides of the stock lament/'n.vmisnd :arruinar-ste another Q7 form oflfreshxair system.` Thissystem provides spaanse "f l thjf corridoi-V f in Figure r. II is a" plenum, fandservesl "substantially the same pur- "h snllearried on bearings sz, `mounted on bearing ads. Ihefbearings mayfbe suppliedQwith `lui t ono'f the Jfans, is in twocounteractingcun, Il inonefdirectionof fan rotation; and vin counsubstantially `laterally in dinerent directions from Justshleljihy:anyfsuital'ile 'meansto control the condamner for each directions: rotation or *are employed and air isintakenfrom the con-y 1 locust. 'Ijhejfcfndt lsmsybeluseo with any Lcei s gnofductsystemto,takednfresh air from a conduitradiacentlipakzcloscdside of the suction for intake of fresh air into the kiln chamber from theoutside through both of the fresh air conduits and il simultaneously in either direction off. l fan rotation. .In .thesel figures` I `also illustrate automatic means" for making available fresh "air to thesuction sideofthe fans from both conduits "Wand Il in either directionoffanrotation. This may belaccomplished by `employing right" angle dampers il pivotally attached to pins 10. mount- `ed in `bearings "I i; `Lin Figure `XII the top bearing `'l I'is` shown n.diustalznle. These Vright angle dampers l! are preferably veryfreely mounted so that the dempers may have free movement through an arcof substantially 90, as illustrated in` Figure i IX, to openthe air duct` Il `and to close athe air lport` `Il `vvhenthe` fans are blowingfrom the" `rcompartmrits 180 into the passageway l I` Vdue `to thefinfiuence of suction and pressure respectively* vi` in thelcompartments `Il `land the passageway 13 I forfexaxnple l i Irpreferably provide this system. of freshair` controlnwhena" large volume of fresh air is re` quired inthe kilnyand when it is desired touti- Illze bothffresh, air conduits land .I simultaneously. U'I"hisuautomatic:damperfmay' be `used in connectionwithloniy oneconduitfn or Illif desired andthe other conduit may be omitted.

kiln f independent or. its fresh i air supply. `Automatic meansofoperating the ventilatordampers fl-14 mdWI;` comprisingvmotorflevers lIiiand 18 respectively, which. are controlled byr the .-wet i bulb temperature within the kiln; `as byl any well known type ofi` controller Il andll respectively.

' Ipieferably provide anysuitableand preferred system of humidifying the atmosphere of the kiln.

Il are on another side; each extending substan- :tlally one haii'` the length1 of the kiln. Automatic` meansofwoperating` the sprays ll and ",and Il comprising diaphragm valvesV I1 andy" respectively; which may becontrolled by the wet bulbV L temperature within the kilnasb'y any well known ftyperof controllerliland llxrespectively. A

l l `I `preferably:` provide doors and Il` for the .fresh Jairf conduits Il and Il `at the two ends respectivelyof the kiln. These doors may be opened and closed `by the controllers Il andvll, respectively, of any well` known type `which are `actuated by fluctuations of` temperature within f the kiln as causedby the nuctuations of the drying rate of` the stock. Forexample, the `motor levers. Ii and llvwluchcontrolthe fresh lfair `doors l Il `and llrespectively at .opposite ends off the kiln in Figure VI, may be actuatedto close fthefresh airconiiuit4 doors and, for exami ple, when the vwet bulbjtemperaturewithinthe i kiln atthe wet bulbs I3 and!! respectively, falls l below the set point.` v"Iheymay actuatethe motor i v levers" and," respectively to open thefi'esh `air doors Il and..." respectively, for example.` .when the wet `bulb temperature within the kiln exceedsfthe set point ofthe Icontroller. @Theyoperation of the fresh air doorsmay be simultaneous` )with the operationfof `the ventilators automatictventilation. control is em- .pioyedg `Both ireshulair doorslyand ventilators may alsobe operated `simultaneously with the iol I, vI preferably 4 Y operation `of the steamsprays-that is. when the f. steam .sprays are turned on at either end of the kiln,xthe fresh-air doors and ventilators at rthat end are closed, and when the humidifyinlr` Mays 5 are turned oifthefreshairdoors and ventilators may rbeopened. vThis may be accomplished by employing diaphragm valves and Il loppositely acting to motor levers I1 and 1I, and land 1l respectively.y That is, the diaphragm valvesA preferably open Ywith air pressure from thecontrollers I. and Il, and the motor levers vclose theventilaters and fresh air doorsfwhen air pressure is on Fresh air and ventilation are utilized when the wet .bulb temperature within the kiln exceeds the setA point; It is understood that the fresh air `and ventilators may be operated independently or together, also operated independently of they steam sprays or simultaneously' with the steam spraysif desired-.

*1" preferably provide heating "systems on two sides ofthe circulating`=system.f An important `'feature of my inventionis in the controlof heat ywithin the kiln chamber.l Infmy `application Se'- rial #492,026, I employ means `for'creating uniform temperature and drying conditionsby creating longitudinal circulation in two independent circuits from the center toward the ends of the kiln in one direction of fan rotation and tion.' In my present invention I employ trans- Averse circulation without .substantial longitudinal fair movement.- Mo 1e:unifl"lrm.` heatsdistribution provided by my 'present invention is accomplished by the employment of separate heat control and substantially uniformy drying ateach of the two ends of the kiln, regardless of the differences in moisture contentof the stock at the two ends of thekiin.A ,.y

provide individual. heating Vsystems Il, l2, and Il supplied with steam from an outside source through thev pipe li. Heating systems Il and l! are for. supplementary use and are n 1 at the two ends respectively ofthe kiln, separately dl controlled by any well-known type of automatic [controllers and Il respectively, each having thermostaticdry and wet bulbs within the kiln. ll'ior example,.thecontroller 8l. has dry'and wet bulbs $2 and I respectively, and the controller il l has dry and wet bulbs and Il respectively. The

dry-bulbs l2 and Il controlthe temperature within the kiln at the twoends respectively, and actuate theeontrollers. to open the diaphragm valves I l and Il byair pressurewhen thetem- I6 perature within thekilnk at the two ends respectively drops below the :set-pointv as maybe caused by a slowing up of thedrying of the stock. 'Ihe wet bulbs are preferably keptwet by water boxes III, with wicks `l Il anda water supply through the pipes lli supplied with 'water from'a source not illustrated. In some cases I employ heating pipes v`Il between' the stock loads as illustrated for example in Figure II; in addition `to the pipes described above. The pipes Il are `preferably individuallycontrolied at 'the two ends of the kiln. The heating system Il preferably extends the Afull length of the kiln. It is in the path of air cir- Aculation of the fans and a substantially uniform heat distribution is e'ected substantially the full length of the kiln.` 'Ihe uniformly distributed heating system .and/or air circulating system [effect uniform heating conditions .within the kiln y "substantially its full length when the initial moisture-content lof the stock is substantially uniform.

- 75 This is rarely the case as stock usually varies in vice versa in the opposite direction of fan rotaosmose I l inltiaifnuimm coment. n is, therefore, asuntageous to employ a separately controlled heating system and/or humidifying and Ventilating systems at each endof the kiln in vaddition tothe uniformly distributed heating and air circulating systems, to provide extra heat, and/or moisture and Ventilating capacity to dry. the faster drying higher moisture content stock in the same length of time as the slower drying lower moisture content stocks In addition I preferably employ a separately controlled heating system at each end of the kiln, but when this is donc other units of ,theheating system may extend the full length of the kilnas.- for example, the heating unit Il. This unit nay be supplied with steam and controlled by hand or by the diaphragm valve I6 or l!y which supplies the heating system at either end .of the kiln. The individually controlled heating systems at the two ends of the kiln are supplementary and must be of sui'ilcient capacity to permit carrying the desired temperature in the end ofthe kiln to which it is located as required byl the -varying moisture content of the stock therein. The separately controlled heating systems at the two ends of the kiln permit a uniyformity of drying not possible without it.

In my invention I preferably employ a strictly transverse circulation of kiln atmosphere, discharged from the opposed right and left hand fans and recirculated in a direction substantially transverse to thelongitudinal axis of the kiln.

t Air is discharged in either direction of fan'rotation in counteracting currents and it is normal for these currents to spread between adjacent compartments so as to cover the space between fans and provide a uniform flow of air circulation transversely within the kiln` and across the stock therein, in either direction of fan rotation. ever, it is an important feature of my invention that each -pair of fans substantially recirculates the air within its influence so long as the air remainsv within the kiln, without effecting longitudinal air movementwithin the kiln proper from any one fan substantially beyond the median line between fans in each circuit of aircirculation. Because the fans are ci'y substantially uniform v volume and are rotated at the same R. P. M., there is no tendency for the air to move longitudinally ywithin thekiln, whichis essential in connection with myinvention.

An essential feature is also the sectional control ci' drying conditions which is preferablyindependent at the two ends of the kiln, regardless of the amount of water contained within and to be evaporated from the stock at the two ends of the kiln. Y The circulating system, the heating system, the humidifying system, the fresh air system and the Ventilating system is each'designed to provide adequate circulation, heat, humidification, fresh air and ventilation respectively in each section of the ,kiln in which it is located. This inter-related sectional control of these systems provides a uniformity of drying that is not possible without it.

By means of the independently controlled systems I am able to control the drying independent of variations in thel amount of moisture to be evaporated at the two ends of thekiln. I employ a well known type of temperaturev and humidity recorder controller` which controls'the dry'bulb temperature by turning on and off` a supply of steam through diaphragm valves, for exampl,-to the heating pipes, whichrvalves are lactuated by the dry bulb thermostat'- This controller also controls the wet bulb .temperature by means of the wet bulb thermostat which may aetuate dia- HOW- 9 the `positiinro .kiln, and also` actuate motorlevers[controlling `fresh air `ductsfancliventilators at the dilljerent lends of tho liiliil trahi able iovhiaihtoih ldryig conditions@ attire-@two ends of fthe kiln Whichwill u substantially uniformly dry stock varyingfin inidry an t bulb temperatures.

strilmohcs aroxcoinmorily; used oh dry `kilns ano are known? est tmeer,alture and* humidity" reoorder"` controllers;

dry "or Wet` bulb i temperature ixlvithin the kiln at nient is operedtosupplyair from theiauxii sour-'ce Hto the: diaphragm valvesf `toV the motor levers,orbothlpAnv well-known mtiiftcentrollermaybe employed; '-hwver," S0 `longffas itfmay be usejdtoicontrol thebdry andlwet bulbjtemperatu s lthin the'jkiln above 'cle-` trates the design ofi `liaphraghi jivalves as; in, 79a; andina he ,ventilators may befof` any Well-known` type, forexarrple, such as" shown in'FlgurexXand "throughthepipesyllandil respectively Fig?` i U or ii-hoi vehtlloiaors 1s respeotlyoly; The

one endof thelkiln, `butitis understood that lphragln valves E Sfan {Q'Lqandlthe motoril levers` and `J5 with the-@onirpllrisulla# theiohmslie n "of the kiln. would be substantially thlefsame, Bearing in mind `that tho oir u oirohlotioht is` ictlytransvese Within thekiln, inpelther dlrecf i ufr the teontrollerf'at each end,`on`ce infeaoh `"circuit i, that lend is hih, theheooreqmedroh empf ration ioflxmolisture is` greater Vand. the 1 temperf ture loss, of the airds groeten l'fhlusthe ther- `rrlostatic bulb 92`,` for example,` at that endctutes the Goontlbller 4lll to open :the heat diaphragm vlve A 011k the Supply `111,1@ te theflietm `Dives i atlthat end.` temperature. In this l "Tpreferably emplovcontolf leurs"whicharconstructcd so that 'when either` the 1 f the therrriosgtatie,"bulbs` reachsfthe i iryi type "of lfautof i i i valves marl be ,fof` i any well( i such for uexaxnpler as illustrated in" y be opened with air pres` i l u u u u `polo:orylnsfio supply i :steam` `o theheating` ipeswithinthe kilmprto thehumidifyiiijg,sprays 'rhe Flguromr illusl "rfleversactuating the duit! mosphereatone end isiraised fabovethefsetpoint i of the controller, oaiisd by awetf condition of,` 1o

the stock being "dried, `the Wet` Q3, for `errant-1 A ple, transmitsthisbonditioh tothecontroller 90; i i `'.l'hy preferably employfan i aurrlliaryl ai1j"`Sl1rI5p1 y ''.to actuatel fthe i {diaphragmfvulves ahdmtor levers."V These" ini andthe vdiaplnagm` motor" controlling tife` vents,` and/or theidlaphragm motor 61 controlling l thej freshfairyjoonluvt doors at that end; opens `l5 thmto reduce "thehulrnidity, or ifv the` wetbuih i temperature drops bytheslow dryingof thestock, the vents `and air `portsatthatfond are closed and the Asteam "spraysfSBor 541 arefopenedby dia-` u i u i zolly phragm valvesllf9xfdesucruibelabove. i i i l "I preferablyprovide`1fans ofzjargertfdameter or` havlngagreaierjohglejofblade,atjtheendsof thehun. u Thefirstifah Blatltherfohd oftho u i kiln; as` illustrated `in Figures Y or Y1, preferably i has a largrlcapaity and protillel` greate volf urnefof` airgcirculation attheendsof,thekilnlin,`

either u u direction` Hof i falli" Qrotation.- greater volume of"`air circulation is i "needed to overcome ends] or i thikilnl.

roofi'on the two sidesof`tleairo1rculatlng system i may be employed Ato serve the` same purpose,.as f f `well `asthepurposeof ventilationandmay, 40

` 1i"gure`}U.` `Thvare shown as closing thefresh f 1 air doors anduventilatorsrby air pressure" supplied automatically controlled in `lile` lmanner.

within the .kilfn.;M xWhenutbe are rotating-in en# direcbin air; temete@ from thegomnortf i ments" upland" dischargedjnto the passegewaysmf 3J i 45 oounteracting" `currents,` and outnthe twolsides `oifieach ofthe passageways; Thedischarged at"` mcgsphere` passesgaross-the heating pipes and up u f vilardlylatitheisidesfot thekiln `and into theinter` Q t 3 i stices of thestockloads,` aorossith stock load l into the plenum` chamber "Mgand theniagaininto in continuouserecirculationy` y l i e uIn the opposite dlretionofuifan rotationyairiis dischargedlveliicallvfromthe passagewaysl in t5 u "counteracthgi i currents into the;4 compartments" 3U, `and thenmoves through theplemlmchamber" I4 or 46;: acrossithestookiloads 6, `orti-12nd "lflnto the plenum chambers "and 48and across the i u heatingipipesizthroughatwosides otpthe passage- 00 i i `Wavs 3 I into "the compartments 30 "in lcontinuous i recirculatiom` In. the `latter direction of` air iciroulatlonirrosh'airhmaybo fulmine@throughi` the air conduits "and the air `drutzilinto 'the pas- I sagevays Whenthe `airiiis being," circulated inthe* former direction airfmay'beftaken" in `through the `conduit `l one` the` air` duets: `ihto i the oompartmeooyan, and thence, roclroulategi withinthe kiln. i

'Bamsgmav be provided at any suitable locaj tion for directing air `across the stockloads, .for

example,v floor I` bailles il i and `ceiling baiiles I9 employed. i

The arrowsfwherever in" the "rirarlrings` way the condition or the lumber: *controls fthe i separate heating system at the endof `the kiln `at u which itis located. lIljthgo temperature ofjth` i i Y `sltirrises` too highyiduetdless heat being"used;forvi` o evaporation of moisturejfromfthe stock than" is 5 Inl-ow care not required` Fresh air `duets throughfthe i 6 illustrate one `dlx'ectionof airA circulation within thekim. Itis understoodthat this invention is not lim ited toy theexact design and formy illustrated and described.A Modicati'ons of the structures and methods herein described and equivalents 'are self-evident togthose skilled'in the art; therefore, it is to be understood that the invention includesfwithin'itsscope' what ever changes fairly wvcome within either the terms or the spirit of the appended claims. y

`Havingl described my invention, what I` claim f yl. In Aa dry kiln, `theffcombination of an air cir- 1 5 culating system comprising spaced compartment aircirculating units, each closed on al plurality of sides and open onA onejof its sides, paired substantiallyy equal capacity fans, oneright hand and ,oneleft hand, voperatively mountedV in the 20 two endsfrespectively'vof cachot said unitsfa ,freshair supply duct to thegs'uction, side of each p'airof fans lin eitherv directionof rotation of `said fans, `one duct extending through one of the closed sides of said unit, whereby the fans may discharge conditionedy atmosphere in opposing currents substantially"transversely through the saidopen side in one direction of their rotation, .and discharge conditioned'air out the ends respectively inthe opposite direction of their rotav tion,` a current from" one compartment unit being opposed by a current from an adjacentcompart- C mentunltf '4 j`f`2.In ya-`*'dry`` kiln, a rotaryv fan `operatively mounted in a-r Afanj-ductdefining wall therein,

, $5 separating suction alndrairdelivery sides of said fan, a fresh air lconduit -withinsaid kiln and communicatingfwithg,the-outside of the kiln, a

ductand an adjacent port communicatingwith said conduit, and `with the suction and air degvlivery sides respectively of said fan;when it is rotating in one direction, a damper operatively mounted to automatically open said port and close said duct by suction and pressure from said fan, and to automatically close` said port and open said duc'twhen the fanY is`rotating-in .the opposite directionfwhereby air is intaken to the suction side of said fan through-said conduit in either direction of fan rotation. y

i3. In a dry kiln having therein stock varying in initial moisture content, a substantially uni- Iormly distributed transverse aircirculating mean's therein, aheating means extendingfsub` stantially the Iullle'ngthof the kiln .for supplying a Lsubstantially uniform 'amount of heat the full length of thekiln, individual heating systems at each end ofthe kiln, a controller at each end forfthe individual heatingv systems, each contmlier having av thermostat in the path of the transverse. air circulation adjacent to the stock loads at its respective end, whereby variation of the temperature lfrom a. predetermined amount at each end, eiected'by the dryingrate of the A stock adjacent thereto,vcontro1s the` heat supplied'respectively to said heating systems.

4. In a dry kiln adapted for having stock loads therein, a door rvat one end thereof, a distributed air circulationgsystem forv effecting transverse circulation'therein, said air circulation system comprising a larger capacity fannat the end thereof adjacent to said door, a heating system in said kiln disposed inthe path of transverse air circulation, extra extended surface radiation v'on said heating system adjacent to said door, said radiation beingin the path of air delivered by 'said larger capacity fan, whereby the same temperature and drying rate of thestock may be maintained adjacent to the door, as in the remainder of the kiln.

s 5. In a dry kiln adapted for having stock loads therein and having a door at one end thereof, a distributed air circulation system lcomprising fans,` for effecting transverse circulation therein, said air circulation system comprisingl a fan of larger capacity at the cnd thereof adjacent to said door than fans remote from said door, a heating system extending substantially the full length of the kiln, a separate heating system at each end, said heating system disposed in the path'of transverse circulation from said fan, control means having a thermostatin the path of air circulation at each end of the kiln, for each separate heating system whereby the extra air circulation adjacent to said door across said heating systems makes the latter more effective, adjacent tothe door, than in the remainder of the kiln. 6. The method of drying stock varying in initial moisturer content in' a dry kiln, which consists of expending substantially the same amount of heat units to the air substantially the'full length of the kiln to give it a predetermined temperatur'e, of :circulating the uniformly heated air transversely across said stock in the different sections longitudinally in the kiln, of determining the temperature of the air after it passes across the stock as a gage of the drying rate of the stock atvthey different'sections, and of supplying additional heat to the airvin ysuch section which is low in temperature to Icompensate for the loss of heat belowr the said predetermined temperature, which loss was effected by a faster drying rate'of stock in that section.,

'7. In a'dry kiln, an air circulating compartment unit therein, open on one of its sides, substantiallyequal capacity right and left hand fans inl its twoiends respectively, an individual air duct communicating with the outside of the kiln and 'with ,the interior of said unit, heating means on each of two sides of said unit whereby upon rotation of the fans in one direction fresh air is induced into the unit and mixed with the kiln atmosphere, sucked into its open side and the mixture dischargedr out the two ends of said `unit in opposite directions across both of ywith the outside ofthe kiln and eachdisposed on a different side of the kiln, a fresh air duct and portleading from each of said conduits, said ducts communicating with the suction side of said fan and said ports communicating with the air delivery' side of said fan when the fan is rotating in one direction, two automatic substantially right angle 1dempers, one pivotably mountedon each side of said fan between said duct and said port whereby said port is automatically opened and said duct is automatically closed when the fan is rotating in one direction and said port is automatically closed and .said duct' is automatically opened, when the fan is rotating in the opposite direction.

9.v In a Adry kiln a rotary fan operatively mounted therein, a fresh air conduit within and 'communicating with the outsideiof' the kiln, a

fresh air duct anda port communicating with the suction and air delivery sides respectively of said fan, an automatic damper substantially shapedvas a right angle plate pivotably mounted to automatically open said port and close said i ductwhenythenfan isrotating in one direction, and to automatically close said port and open positeqdirection. l i Y 10; `In adry kilnhaving therein stock varying 1 ffin moisture content," a substantially uniformly n distributedV transverse "air circulating means `ltiallyffthe full lengthof` the kiln for supplying ,a substantially uniformA amount ofy humidity the ,i full length of Ithe kiln,` an ,individualV humidifying systemat eachfend of the kiln, a controller the stock loads at its respective end, `whereby variationofithemwet bulb temperature` from `a predetermined `amount `at each end, effected` by 1 the `dryingnrate fof the stock `adjacent thereto,

1v humidifying system 11. In `a `diyQkiln having therein istockfvarying din? moisture content, a `substantially uniformly therein, aliheatingmeans extending snbstantially the full `lengthl ofthe 4kilnfor supplying heatA substantially the full lengthof the kiln, an `inwdividual heatingsystemat each endof the kiln; an individual Ventilating system at each end oi the kiln,` a dry bulb eontrollerat eachVend for the individual heating systems and a wet bulb `glating systems, each controller` havinga thermosaid fduct` when` thenjfanisrotating in :the op-` at each end for, the individual humidifying systems,eacncontrolierhaving a thermostat in the l ,i path ofthe transverse air circulation adjacentto controls steam supplied respectively to said distributed transverse air circulation means controllerv at each end for the individual venti-L fstat in` the pathofthe transverse air circulation i adjacent to thestock load at its respective end,

whereby variation ofthe wet` and dry bulb tem- `peratures from predetermined "amounts at each end, e'ected by the drying rateof the stock ad- `jaoent thereto,` controls respectively the `venti- Vlation, Vandheat supplied tothe heating system Vat each end.` o" therein, a humidifying means extending substan- 12. `In a dry kiln, a

duit therein `communicating with the outside of reversible fan operatively i l mounted in a fan ducttherein,` a fresh airconair delivery `sides of said fanand an angle damper `pivotably mounted in said fresh air duct and 'porti for alternately permitting the` intake offresh air throughsaid duct and said port. de- Y pending upon the direction of rotation of said fan.

ly distributed transverse `air circulating means `meansateach end of the kiln, andafdrybulb temperature controller at eachend `o1 thekiln for. the individualheating means, each dry bulb controller having a thermostat in` the path of i transverseair circulation adjacent` to the stock` loads at its respective end.

JAMES` FoRREs'r COBB;

13. Ina dry kiln having therein stock varyingin moisture content, a substantially uniform- Stherein, a stearn` spray extending substantially 

